The present invention relates to an image recording device, and more particularly to an image recording device in which image receptive members are delivered one by one from a stack, and images recorded on a photosensitive member are transferred to the image receptive members for form images on the latter, the image recording device being capable of detecting a shortage of remaining image receptive members for allowing wasteless and efficient image formation.
One example of image recording member in the form of microcapsules containing a photosensitive composition is disclosed in Japanese Laid-Open patent publication No. 57-179836. The disclosed image recording member is a photosensitive member which employs capsules having a synthetic high-molecular resin wall containing a vinyl compound, a photopolymerization starter, and a colorant precursor. With this photosensitive member, microcapsules are hardened in the pattern of an image through exposure, and then the microcapsules which have not been hardened are broken under pressure to discharge the colorant precursor which then forms a colored image. A high-quality image can be obtained by a simple dry-type process. However, the disclosed photosensitive member is much lower in photosensitivity than photosensitive members which use silver halides such as photographic emulsions.
There has been developed a novel photosensitive member which has high sensitivity and can be processed to produce a high-quality image through a simple dry-type process (see U.S. patent application Ser. No. 868385). The photosensitive member comprises a support coated with a photosensitive silver halide, a reducing agent, a polymerizable compound, and a color-image-forming material. At least the polymerizable compound and the color-image-forming material are encased in one microcapsule.
An image recording device for recording an image using such a photosensitive member is disclosed in detail in U.S. patent application Ser. No. 942654. In the disclosed image recording device, the photosensitive member is exposed to an image to produce a latent image thereon. Then, the photosensitive member is heated to develop the image by polymerizing the polymerizable compound in an area where the latent image is present, thus generating a high-molecular compound to harden microcapsules. Finally, the photosensitive member is superposed under pressure on an image receptive member having an image receptive layer to which a color-image-forming material can be transferred, so that at least some of microcapsules in an area where no latent image is present are broken to transfer the color-image-forming material to the image receptive member for thereby forming a visible image.
In the image recording device, the photosensitive member is fed through an exposure unit for forming a latent image and a heat development unit for heating the photosensitive member, after which the photosensitive member is superposed on the image receptive member. The image receptive member, on the other hand, is not especially treated until the photosensitive member is superposed on the image receptive member. To meet demands for a smaller device size and layout requirements, the feed path for the image receptive member is usually shorter than the feed path for the photosensitive member. Therefore, if the image recording device ran short of any image receptive member while the photosensitive member is being exposed or heated, no image would be transferred from the photosensitive member that has been exposed, and the photosensitive member would be superposed on no image receptive member, with the result that the color-image-forming material would be deposited at various locations in the image recording device.
Various countermeasures have heretofore been proposed to avoid the aforesaid drawbacks. For example, a certain number of image receptive members are loaded in the image recording device, and those image receptive members which are supplied for operation in the device are counted by a sensor or the like so that the remaining number of image receptive members can be detected. When a predetermined number of remaining image receptive members are detected, the exposure process of the photosensitive member is interrupted. In this manner, the problems as described above can be avoided.
However, if two or more image receptive members are fed at a time, then the detected number of remaining image receptive members is false, and image transfer may be made impossible. Accordingly, a mechanism for detecting feeding of two or more image receptive members at a time is required rendering the overall arrangement complex. Where a means for storing data on the remaining number of image receptive members is an electric means such as an IC memory or the like, a backup power supply should be provided to protect the stored data when the image developing device is not in operation.
According to another proposal, recesses or the like are defined in some image receptive members near the end of their stack, and whether the device is running short of image receptive members can be detected by sensing the recesses. This arrangement is not economical since special image receptive members are needed for detecting purpose.